CVE-2019-18218 number is incorrect in main/file/APKBUILD

When CVE-2019-18218 was fixed in #10911 (closed) the CVE number added in main/file/APKBUILD is wrong by a digit (9 instead of 8):

 # secfixes:
+#   5.36-r1:
+#     - CVE-2019-19218
 #   5.36-r0:
 #   - CVE-2019-8904
 #   - CVE-2019-8905

CVE-2019-19218 does not exist.

This is bad because those are used to create automated vulnerability databases like alpine-secdb and vuln-list which alert users to a nonexistent CVE. We found it because Clair started flagging our alpine containers as having this CVE which we couldn't find in the CVE database.